most are actually turned by fingers as drills can be excessive and the canal of the tooth is shaped and prepared from smallest file size up to the largest it can take, usually they use fingers as there a better feel for it then to use a drill (other than a gates glidden to remove gutta percha
Gates Glidden by SybronEndo or lentulo spiral to work ah26 or rc prep down ) there maybe a chance of perforating the tooth and you can kiss the root canal good bye, most are referred to an endodontist but we still do in the government free health clinic from the premolars to the central incisors.
and yes nate they all look like 15's to me, that to me was the dead giveaway in your first pic post and no 12 post i mentioned the number to check with you all that my eyes were seeing 15 as well.
post 4 of Nates shows the drill type there is a interlocking catchment that engages in the slowspeed drill, some use these but most going the finger method and a root canal can take 3, 1 hour appointments if successful
may have used part of the file to nail/tack/heated pushed through soldered on the other side of silicon? it to the circuit board but not to stick into our mans (Jeremy Bulloch) head as they dont seem to butt up flush with the board (shadow, but could be angle)
http://www.thedentedhelmet.com/f23/found-part-helmet-keyslot-circuit-board-4206/ kept this way so thay could be tweaked in different directions but without workhardening the metal (file metal) and snapping it off
Nate i reckon you hit a home run here and would bet 100% that this is what they are the 15 is the absolute seller for me! great find